SOS 诱导的 imuABC 水平对新月柄杆菌自发诱变和损伤诱导诱变的影响。
Effect of SOS-induced levels of imuABC on spontaneous and damage-induced mutagenesis in Caulobacter crescentus.
作者信息
Alves Ingrid R, Lima-Noronha Marco A, Silva Larissa G, Fernández-Silva Frank S, Freitas Aline Luiza D, Marques Marilis V, Galhardo Rodrigo S
机构信息
Department of Microbiology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil.
Department of Microbiology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil.
出版信息
DNA Repair (Amst). 2017 Nov;59:20-26. doi: 10.1016/j.dnarep.2017.09.003. Epub 2017 Sep 14.
imuABC (imuAB dnaE2) genes are responsible for SOS-mutagenesis in Caulobacter crescentus and other bacterial species devoid of umuDC. In this work, we have constructed operator-constitutive mutants of the imuABC operon. We used this genetic tool to investigate the effect of SOS-induced levels of these genes upon both spontaneous and damage-induced mutagenesis. We showed that constitutive expression of imuABC does not increase spontaneous or damage-induced mutagenesis, nor increases cellular resistance to DNA-damaging agents. Nevertheless, the presence of the operator-constitutive mutation rescues mutagenesis in a recA background, indicating that imuABC are the only genes required at SOS-induced levels for translesion synthesis (TLS) in C. crescentus. Furthermore, these data also show that TLS mediated by ImuABC does not require RecA, unlike umuDC-dependent mutagenesis in E. coli.
imuABC（imuAB dnaE2）基因负责新月柄杆菌及其他缺乏umuDC的细菌物种中的SOS诱变。在这项工作中，我们构建了imuABC操纵子的操纵子组成型突变体。我们使用这种遗传工具来研究这些基因的SOS诱导水平对自发诱变和损伤诱导诱变的影响。我们表明，imuABC的组成型表达不会增加自发诱变或损伤诱导诱变，也不会增加细胞对DNA损伤剂的抗性。然而，操纵子组成型突变的存在挽救了recA背景下的诱变，这表明imuABC是新月柄杆菌中SOS诱导水平下跨损伤合成（TLS）所需的唯一基因。此外，这些数据还表明，与大肠杆菌中依赖umuDC的诱变不同，由ImuABC介导的TLS不需要RecA。
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